Study Finds Marijuana Use Linked to Increased Sperm Count

Men who have consumed marijuana have higher sperm counts than those who have never used it, according to a new study published in the February 6th issue of the journal Human Reproduction.

This longitudinal study “included 662 subfertile men enrolled at the Massachusetts General Hospital Fertility Center between 2000 and 2017.” The men “provided a total of 1143 semen samples; 317 men also provided blood samples in which we measured reproductive hormones.”

Researchers found that “Men who had ever smoked marijuana had higher sperm concentration and count and lower serum FSH [follicle stimulating hormone] concentrations than men who had never smoked marijuana; no differences were observed between current and past marijuana smokers.”

The following is the method researchers used to come to this conclusion:

Use of marijuana and other drugs was self-reported at baseline. Standard protocols were followed for measuring semen quality, sex hormones and DNA integrity. We used linear mixed effect models with a random intercept to evaluate the associations of self-reported marijuana smoking at enrolment with semen parameters from subsequently collected samples, and linear regression models for sperm DNA integrity and serum reproductive hormones, while adjusting for confounders including smoking and cocaine use.

Below are the main results of the study:

Men who had ever smoked marijuana (N = 365) had significantly higher sperm concentration (62.7 (95% confidence interval: 56.0, 70.3) million/mL) than men who had never smoked marijuana (N = 297) (45.4 (38.6, 53.3) million/mL) after adjusting for potential confounders (P = 0.0003). There were no significant differences in sperm concentration between current (N = 74) (59.5 (47.3, 74.8) million/mL) and past marijuana smokers (N = 291) (63.5 (56.1, 72.0) million/mL; P = 0.60). A similar pattern was observed for total sperm count. Furthermore, the adjusted prevalence of sperm concentration and total sperm motility below WHO reference values among marijuana smokers was less than half that of never marijuana smokers. Marijuana smokers had significantly lower follicle stimulating hormone (FSH) concentrations than never marijuana smokers (−16% (−27%, −4%)) and there were no significant differences between current and past marijuana smokers (P = 0.53). Marijuana smoking was not associated with other semen parameters, with markers of sperm DNA integrity or with reproductive hormones other than FSH. Chance findings cannot be excluded due to the multiple comparisons.